An electrochemical biosensor is a biosensor which uses bioactive substance (such as enzymes, antibodies, nucleic acids, cells and the like) as bioreceptor) and uses an electrode as a signal converter to convert biochemical signals into electrochemical signals so as to achieve the detection objective. The electrochemical biosensor uses potential, current or capacitance and other electrical signals obtained on the electrode as feature detection signals, has the unique advantages of being simple in instrument, low in manufacturing cost, easy to miniaturize and able to achieve onsite instant detection while having high sensitivity and selectivity, and thus has been widely used in biomedicine, food analysis, environmental monitoring and many other fields.
The traditional electrochemical biosensors can be divided into labeling type biosensors and label-free type of biosensors according to the way of generating the electrochemical signals. The labeling type electrochemical biosensors have been replaced by the label-free type electrochemical biosensors due to complex operation and high cost resulting from that methylene blue, ferrocene and other electroactive substances need to be labeled on DNA chains. The label-free type electrochemical biosensors omit the labeling steps and directly perform the detection by using the electroactive substances in base solutions, such that the cost and the operation complexity can be greatly reduced. However, due to the use of the base solutions, the application range of the label-free type electrochemical biosensors is limited, the back signal is large, the sensitivity is low, and the stability is poor.
Therefore, a label-free type biomolecule detection method with high sensitivity and good stability is needed urgently at present.